Encyclopedia of grille knowledge, too timely
What are the main process parameters of the grille?
(1) The main process parameters of the grille include raster distance, grid flow rate and water head loss. The distance between the grille distance is the distance between the two adjacent grids. The grille distance is greater than 40mm. The grille distance between 20 and 40mm is the middle grille, and the grid distance is less than 20mm.
(2) Perform flow rate refers to the speed of sewage flowing across the grid and grille channel. The firing speed of the grid cannot be too large, otherwise the soft debris that should be intercepted may be rushed over. The overcare flow speed is too small, and the sand particles with a large particle size in the sewage may be deposited in the front channel.
(3) The loss of the sewage over the raster head refers to the poor water level before and after the grille, which is related to the speed of the grid. If the loss of the raster head increases, it means that the grid flow increases. At this time, it may be that the amount of water over the grid increases, and it is more likely that the grille is blocked and needs to be cleaned in time. The loss of the water head of the grid is reduced, indicating that the grille flow rate is reduced, and we need to pay attention to take measures to prevent sand in the front channel.
What are the principles of grid selection?
(1) The grille is divided into two types: manual grille and mechanical grille. In order to avoid the poisoning of pollutants to the human body, reduce the working intensity of workers, improve work efficiency, and achieve automatic control, mechanical grille should be used as much as possible. When the sewage contains oil such as oil and other volatile gases, the power device of the mechanical grille should have explosion -proof facilities.
(2) Determine the specific form and material of the grille according to the height of the water quality of the sewage, such as the height of the pH value, the size of the solid.
(3) Large sewage treatment plants generally set two grilles and one sieve net. The spacing of grille strip should be determined according to the type, flow, representative debris types and size of the sewage, which can not only meet the water pump structure of the water pump structure The requirements are required to meet the requirements of subsequent water treatment structures and equipment. The first lane uses thick grille (50 ～ 100mm) or medium grille (20-4omm), the second use of the middle grille or fine grille (4 to 10mm), and the third is the screen (<4mm).
(4) Five types of grille strips are 20mm square, 20mm in diameter, 10mm × 50mm rectangle, 10mm × 50mm rectangle with a semi -round head, and 1OMM × 50mm rectangles on both sides. The circular grille bars have good hydraulic conditions and small water flow resistance, but they have poor stiffness and are vulnerable to external forces. Therefore, it is best to use a rectangular section when there is no special needs.
(5) The grille is generally installed at the head of the processing process or the water inlet of the pump station. It belongs to the throat. In order to ensure safety, there must be a spare unit or other means to ensure that the grille is maintained in the case of non -stop water.
(6) In order to protect the power equipment, the mechanical grille is generally installed in the ventilated grille. The large and medium -sized grille is asked to configure the installation of the installation of the transportation equipment to facilitate the daily removal of the equipment maintenance and grid.
What are the basic requirements for grille installation?
(1) The channels in front of the grille should be kept by a direct pipe section of more than 5m. The water flow rate in the channel is 0.4 to 0.9m/s, and the speed of flowing through the grid is 0.6 to 1.0m/s.
(2) The connection between the channel where the grille is placed and the front channel of the grid should have an expansion angle of less than 20 °.
(3) The installation angle of the grille is 45 ° to 60 ° when the artificial scum is cleared, and the mechanical clearance is mostly 70 ° to 90 °.
(4) Losses through the water head of the grille are generally 0.08 to 0.15m. Therefore, the back grid channel is reduced by 0.08 to 0.15m than in front of the grid.
(5) The effective water area of the grille is calculated based on the grid flow rate of 0.6 ～ 1.0m/s under the design flow, but the total width of the grille is not less than 1.2 times the width of the water pipe canal.
(6) The upper part of the grille must be provided with a grid top working platform, which is high by the highest design water level before the height is above 0.5m. Safety facilities and flushing facilities such as railing on the workbench. The aisle between the two -sided platform should not be less than 0.7m. The width of the front aisle should not be less than 1.2m when the residue cleansing, and the mechanical clearance is not less than 1.5m.
How to determine the distance between the grid?
When the grille is set up before the wastewater treatment system and the grid is removed by a mechanical residue machine, the spacing spacing is generally 16-25mm, and when the grid scum is removed by artificial clearance, the spacing distance is generally 25-40mm. When the grille is set in front of the pump, only the sewage is needed or discharged, the grid spacing should meet the requirements of the pump structure. Generally, the minimum gap of the pump impeller.
What are the precautions for grille operation management?
(1) Regardless of the form, the operator should be inspected regularly. According to the water level difference or the number of grids in front of the gate of the grid and the grid, the residue scum is cleared in time. Exclude various faults it occurs in time.
(2) Check and adjust the traffic regulating valve in front of the grille to ensure the uniform distribution of the grid flow. At the same time, the number of grille tables that is put into work is controlled to control the grid flow speed within the required range. When the grid flow is too high, the number of grille tables that invest in work appropriately; when the grid flow is low, the number of grille tables that invest in work appropriately.
(3) As the running time is prolonged, sand may accumulate within the channel before and after the grille. It should be regularly inspected and cleaned the sand to analyze the cause of sand accumulation. If it is the reason for rough channels, it should be repaired in time.
(4) Regularly determine the number of daily slag, and explore when the amount of grid residue is large in one day, January, or a year, in order to increase the operating efficiency, and determine whether the grille operation is normal through changes in the grid volume.
(5) There are often many organic objects such as volatile oils in the grid residue, which can produce odor after accumulation. Therefore, the grid residue should be cleared in time and often maintains ventilation and ventilation between grille.
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